Grill insert



FIG. 1 is a front view of a grill insert, showing a new design;

FIG. 2 is a back view thereof, symmetrical to the front view;

FIG. 3 is a first side view thereof;

FIG. 4 is a second side view thereof, symmetrical to the first side view;

FIG. 5 is an isometric top view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof. 

The ornamental design for a grill insert, as shown and described. 